Bertram Ludäscher

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Many scientific disciplines are now data and information driven, and new scientific knowledge is often gained by scientists putting together data analysis and knowledge discovery “pipelines”. A related trend is that more and more scientific communities realize the benefits of sharing their data and computational services, and are thus contributing to a(More)
1. Background Most scientists conduct analyses and run models in several different software and hardware environments, mentally coordinating the export and import of data from one environment to another. The Kepler scientific workflow system provides domain scientists with an easyto-use yet powerful system for capturing scientific workflows (SWFs). SWFs are(More)
The MIX mediator system, MIX<italic>m</italic>, is developed as part of the MIX Project at the San Diego Supercomputer Center, and the University of California, San Diego.<supscrpt>1</supscrpt> MIX<italic>m</italic> uses XML as the common model for data exchange. Mediator views are expressed in XMAS (<italic>XML Matching And Structuring Language</italic>),(More)
We study the problem of rewriting queries using views in the presence of access patterns, integrity constraints, disjunction, and negation. We provide asymptotically optimal algorithms for finding minimal containing and maximal contained rewritings and for deciding whether an exact rewriting exists. We show that rewriting queries using views in this case(More)
Ecologists spend considerable effort integrating heterogeneous data for statistical analyses and simulations, for example, to run and test predictive models. Our research is focused on reducing this effort by providing data integration and transformation tools, allowing researchers to focus on “real science,” that is, discovering new knowledge through(More)
Recent years have seen a dramatic increase in research and development of scientific workflow systems. These systems promise to make scientists more productive by automating data-driven and computeintensive analyses. Despite many early achievements, the long-term success of scientific workflow technology critically depends on making these systems useable by(More)
| The closely related research areas management of semistructured data and languages for querying the Web have recently attracted a lot of interest. We argue that languages supporting deduction and object-orientation (dood languages) are particularly suited in this context: Objectorientation provides a exible common data model for combining information from(More)
Scientific workflow systems are increasingly used to automate complex data analyses, largely due to their benefits over traditional approaches for workflow design, optimization, and provenance recording. Many workflow systems employ a simple dependency model to represent the provenance of data produced by workflow runs. Although commonly adopted, this model(More)
In this paper, we introduce the Open Provenance Model , a model for provenance that is designed to meet the following requirements: (1) To allow provenance information to be exchanged between systems, by means of a compatibility layer based on a shared provenance model. (2) To allow developers to build and share tools that operate on such a provenance(More)